Effect of Using Lightweight Concrete on the Behavior of L and T- Beams under Combined Stresses

Abstract

This paper presents an experimental investigation for the behavior of flanged reinforced lightweight concrete (LWC) under combined stresses. LWC was obtained through the use of polystyrene foam as a partial aggregate’s replacement to reduce the concrete dry unit weight from 23.0 kN/m3 to 18.1 kN/m3. The experimental work was consisted from two phases; The first phase quantified the mechanical properties of lightweight concrete; namely the compressive and tensile strengths as well as the tension stiffening capability of the concrete mix and The second phase was concerned with testing specimens of lightweight and normal-weight concrete beams (L and T-shaped) under combined stresses for determination of the ultimate resistance, mode of failure, ultimate angle of twist, and load-deflection curve for all tested beams. The experimental program consisted of four full scale T & L beams with cross-section of (150 x 400 mm.). Two T-sections having a width of slab 550 mm and slab thickness of 150 mm, span of 1300 mm, load eccentricity of 50mm, with varying material type (LWC, and NWC). Two L-sections having a width of slab 350 mm and slab thickness of 150 mm, span of 1300 mm, load eccentricity of 50mm, with varying material type (LWC, and NWC).The main variables of this study were the material type, and the shape of cross section. The observed behavior of the light weight concrete specimens up to failure greatly encourages the use of light weight concrete in all structural elements.